Big Indiana Bass

THE IMPACTS OF ENVIRONMENTAL AND ANTHROPOGENIC STRESSORS ON LARGEMOUTH BASS – AN INTEGRATION OF FIELD AND LABORATORY STUDIES
Matthew Van Landeghem

"A bass is a bass" might be a nice statement from the perspective of a pro's advice for finding and catching fish, but biologists are finding out that from a biological perspective, that's not always the case. Largemouth bass were captured from both Illinois and Alabama and held in ponds back in Illinois. Over a period of nearly two years, the fish were tested for their response to cold shock, as well as to overall survivability through a northern winter.

Analysis of blood components during cold shock testing showed that the southern bass displayed a more stressful reaction, and suggested a possible elevation of metabolic rate. This might be at least partially responsible for why the Alabama bass suffered such high winter mortality. On average, about 80 percent of the youngest Alabama bass, and 90 percent of the adults perished during the Illinois winter, while only about 20 percent of the Illinois bass died in any given winter regardless of age.

Impacts of Spawning Habitat Manipulation on Largemouth Bass Year-Class Production in Meldahl Pool, Ohio River
Jason Herrala, D. Baker, and N. Keeton; Kentucky DFWR

The bass fishing in the Ohio River has had a long history of cyclical ups and downs, with the trend being toward poorer fishing rather than better. A lot of theories have been suggested as to why this might be, and several projects have tried to tackle the issue in one form or another. One study effort that was recently finished and documented involved the placement of spawning structures, as well as adjacent Christmas tree cover in several embayments of the Meldahl Pool of the Ohio.

These structures were placed into several creeks beginning in 2004, and continued annually through 2010. Structures were regularly maintained for effectiveness, and there were nearby creeks used for a variety of controls, including some with no structure placement, as well as others where structures were removed to see if any decreases in bass populations occurred.

Nearly 140 hours of electrofishing to assess resident bass populations were conducted over the study period. Across all embayments, the average number of largemouth bass shocked up was 38 fish per hour. Spotted bass were much more scarce, yielding just over 6 fish per hour. For perspective, most of our "tougher" lakes run around 50 bass per hour, while our "better" lakes typically run upwards of 150 bass per hour. The Cannelton Pool of the Ohio R. tends to run much worse (See the table in the link for specific Indiana waters).

Overall, results were consistent and disappointing. In many instances, control creeks without additional structures performed as well or better than ones with the structure addition. In creeks where structures were removed after a period of time, again, there wasn't much difference comparing before and after populations of bass.

The lack of success by adding these spawning structures suggested to researchers that "...the availability of suitable spawning habitat is not the main limiting factor to reproductive success of black bass in Meldahl Pool." That leaves a host of other factors to consider including the amount of river flow, the extent and timing of flooding on a yearly basis, the degree of siltation and/or seasonal oxygen concentration. High river years in 2003 and 2008 resulted in poor year classes of bass, while low water years in 2005 and 2007 produced above average populations.

With spawning structures showing such a poor return on investment, Kentucky DNR personnel have now started to focus on supplemental stocking of 2" bass fingerlings into the embayments of both Markland and Meldahl Pools each June, typically well after most spring flooding has occurred. Early results are encouraging.